Applejack waited patiently in the cave for help, but it seemed like Rainbow Dash was taking forever to come. 

Applejack: Rainbow Dash? Where are ya?

There was no response, she tried calling her friends, but they weren't picking up. Then she tried banging on the boulders blocking the entrance to get attention.

Applejack: Help! I'm trapped!

Meanwhile, Rainbow Dash ran all the way back to camp, she was out of breath.

Fluttershy: Dashie?

Twilight: Is everything okay?

Rainbow Dash couldn't get the words out.

Pinkie: Oh! I know! I know! You went swimming!

Rainbow Dash shook her head. Everyone gave her some time before she could talk again.

Rainbow: Y'know that cave where we got our new magic?

Everyone nodded.

Rainbow: Applejack's trapped in there!

Everyone gasped, astounded.

Rarity: Is she alright?

Rainbow: I don't know, while we were in there, it was caving in, I got out before remembering she was still in there!

Rainbow Dash showed the girls the cave, she heard Applejack banging.

Applejack: Help! Anybody out there?

Fluttershy: Applejack, is that you?

Applejack: Yeah, it's me!

Rainbow: It's alright, AJ, we're all here!

Twilight: How do we get her out of there?

Pinkie: Beats me...LET'S BLOW 'EM UP!!!!

Rainbow: Pinkie, no!

Pinkie tossed a pack of sprinkles at the boulders, that sort of worked but only the top ones fell off, nearly falling on top of Pinkie.

Rainbow: Pinkie!

Rainbow Dash ran into Pinkie, thankfully, she wasn't crushed.

Pinkie: Nice save, Dashie!

Rainbow: *Sigh* I can't risk losing you again, Pinkie. Clearly blowing them up won't work.

Applejack: I can't breathe in here!

Rainbow (frustrated): Yeah, I'm thinking!!!!

The girls did some thinking. Rarity got an idea tried using her diamonds to loosen the rocks, but she couldn't seem to get all of them.

Rarity: I can't loosen them all, ugh, if only Applejack weren't trapped in there, she could remove these rubbish boulders like it was nothing.

Rainbow: ...That's it! Rarity, you're a genius!

Rarity: I am?

Pinkie: Huh, I thought I was always the genius.

Rainbow: Applejack, you think you can push the rocks while Rarity loosens them?

Applejack: Sure, I can try.

Twilight: Rainbow Dash, that's not a bad idea!

Rainbow: Heh, thanks.

Rarity continued loosen the rocks with her diamonds. At the right moment, Applejack used her strength to push the rocks, they collapsed, opening the cave's entrance.

Twilight: It worked!

Rainbow: Applejack!

The girls gathered into a group hug.

Applejack: Boy, am I happy to see y'all! I thought I'd never get outta there.

Rainbow: I'm glad you're okay!

Then, the girls looked into the cave, the magic seemed unfamiliar to them.

Twilight: Rainbow Dash, are you sure this is the same cave as last time.

Rainbow: Uh...did I leave out the new magic part?

Sunset: You didn't tell us there was Equestrian magic here.

The girls went to the center of the cave.

Pinkie: What are these?

Rarity: I don't know, but they look marvelous.

Rainbow: Uh, Rarity, these orbs are probably the source of this evil magic.

Applejack: For some reason, when Rainbow Dash and I found these, I pointed out that we should probably tell y'all 'bout this. Then, the next thing I knew, I was sealed in!

Twilight: Huh, that's too big of a coincidence for that to happen.

Sunset: You're right, someone could be behind this. Maybe someone sealed Applejack in the cave so we didn't know about this.

Applejack: Rainbow Dash was lucky she got outta here on time.

Then, the doubts came back to Rainbow Dash. She wondered, could she be the cause of this? Is Rainstorm Dash breaking through? Are her friends in danger?

Rainbow: I'm gonna go back to camp and think this through.

Rainbow Dash left the group and started making her way back to camp.

https://youtu.be/XTLr_8IvAbc

On her way back, she remembered all the trouble and pain she caused at the Summer Festival. She remembered when the jewel and amulet were reunited and how it transformed her into something very threatening and how she tried to devastate her world by storm. She remembered how addicted she was to the magic and what the results were when it consumed her. She even remembered the pain she brought onto her friends when she injured Pinkie Pie, almost losing her. 

As she was reminiscing, she started weeping softly and fell to her knees. After crying for what seemed like a long time, she fell asleep in the woods. Her friends just happened to be heading back to camp and spotted her on the road.

Pinkie: Dashie, is everything okay?

Fluttershy and Twilight knelt down beside Rainbow Dash, Twilight carried her in her arms. Rainbow Dash snuggled and lay her head on her chest.

Twilight: Guess she just fell asleep.

The girls brought Rainbow Dash to her tent and tucked her into her bed. Applejack put an extra blanket on top of her.

Fluttershy: Poor Dashie. I feel bad for her.

Twilight: I can relate to what she's going through. She seems to be having a rough time and I'm trying to help her push her way through it.

Gloriosa just happened to be looking for the girls and found them in the tent.

Gloriosa: Hi girls! Where have you been?

Twilight hushed her and pointed at Rainbow Dash.

Twilight (whispering): She's sleeping.

Gloriosa: Oh, well, come outside.

The girls left the tent to talk while Fluttershy stayed behind to comfort Rainbow Dash. A little later, Rainbow Dash began whimpering which could mean something wasn't right. Her whimper soon became a sob.

Fluttershy: Dashie? Oh...Shh...

Rainbow Dash continued sobbing hysterically. Fluttershy decided to sing a lullaby to calm her down.

https://youtu.be/-H1Bq8wjkG4

(Found that video randomly online. Trust me, you'll thank me!)

Hush now quiet now

It's time to lay your sleepy head

Hush now quiet now

It's time to go to bed

Drifting off to sleep

Leave exciting day behind you

Drifting off to sleep

Let the joy of Dreamland find you (x2)

Eventually, Rainbow Dash calmed down and continued sleeping peacefully.

Fluttershy: Sleep tight, Dashie.

Fluttershy went to join the other girls.

Gloriosa: So, where have you girls been all day?

Twilight: Well, we were saving Applejack after she was sealed into the cave at the Rock Quarry.

Applejack: All I did was say how we should tell everyone else about it, and then it caved in!

Sunset: We found out there was still magic in the cave.

Pinkie: Except...it's a DIFFERENT kind of magic!

Rarity: There were these marvelous orbs smack in the center. *Sigh* I've never seen anything so beautiful in my entire life.

Twilight: But, like Rainbow Dash said, they could be the source of this magic.

As the girls were explaining what happened, a shadowy silhouette watched from a distance. Fluttershy just happened to notice.

Fluttershy: Look!

Everyone else saw the figure as well, but before they could identify who it was, it disappeared.

Sunset: Hey, come back!

Twilight: Stop!

Applejack: Where'd ya go?

Fluttershy: Who was that?

No one knew who this was, but it was assumed that this person could be the one who was behind all of this.